Differentiating
climatic
and
anthropogenic
alpine
land
cover
change
drivers
from
1972
–
2012
in
the
Cordillera
Blanca,
Peru
Rebecca
J.
Cole
and
John
D.
All
R.
J.
Cole
Institute
of
Arctic
and
Alpine
Research
University
of
Colorado
at
Boulder
cole.rebeccaj@gmail.com
J.
D.
All
Department
of
Geography
and
Geology
Western
Kentucky
University
john.all@wku.edu
ABSTRACT
This
study
combines
remote
sensing
(coarse-­‐scale)
and
ground-­‐based
measurements
(fine-­‐scale)
to
examine
patterns
of
land
cover
change
over
the
past
40
years
in
Huascaran
National
Park
(HNP)
and
adjacent
communal
areas
in
the
Cordillera
Blanca,
Peru.
We
are
testing
how
these
measurements
can
best
be
used
as
predictors
of
vegetation
community
structure
and
to
differentiate
between
anthropogenic
and
climatic
drivers
of
change
in
this
region.
In
addition,
we
are
assessing
how
potential
shifts
in
plant
community
composition
affect
key
ecosystem
functions
including
carbon
and
nutrient
cycling.
Satellite
imagery
including
Landsat
MSS
and
TM,
along
with
ASTER
and
MODIS,
are
used
to
characterize
differences
in
vegetation
and
fire
disturbance
over
time.
Vegetation
patterns
are
assessed
using
NDVI
and
fire
spatial
analysis
is
performed
using
MODIS
thermal
anomaly
and
burned
area
products.
Between
2011-­‐2013,
the
American
Climber
Science
Program
(ACSP)
collected
data
on
vegetation
type,
ground
cover
classes,
and
disturbance
with
an
extensive
set
of
ground
control
points
(>300
10-­‐m-­‐radius
plots)
along
the
length
of
the
Cordillera
Blanca.
In
order
to
assess
if/how
native
forest
stands
have
changed
over
time,
we
are
measuring
the
structure,
composition,
and
patterns
of
regeneration
in
a
series
of
Polylepis
forest
stands
throughout
HNP.
In
order
to
assess
how
upslope
shifts
in
vegetation,
particularly
woody
species,
may
alter
carbon
and
nutrient
cycling,
we
are
testing
temperature
effects
on
decomposition
of
litter
of
dominant
species.
Preliminary
results
show
substantial
increases
in
NDVI
between
3000-­‐5000m
over
the
past
40
years.
Fires
initiate
predominantly
inside
the
park
rather
than
in
the
buffer
zone
and
are
anthropogenic
in
origin.
Vegetation
cover
and
Polylepis
forest
regeneration
is
negatively
correlated
with
grazing
intensity
and
accessibility
to
grazing
animals.
This
research
is
on-­‐
going
in
2013-­‐2014.

INTRODUCTION
The
tropical
Peruvian
Andes
provide
critical
ecosystem
services
to
human
populations
and
harbor
high
levels
of
biodiversity,
including
endemic
and
threatened
species.
These
high
altitude
ecosystems
are
under
increasing
pressure
from
human
activities
including
burning,
deforestation,
and
overgrazing.
In
addition,
the
region
is
undergoing
extremely
rapid
changes
due
to
warming
temperatures.
Glacier
cover
in
the
Cordillera
Blanca,
the
largest
tropical
glacier-­‐covered
area
in
the
world,
has
decreased
by
>25%
in
the
last
40
years
(e.g.,
Rabatel
et
al.
2013)
and
predicted
changes
in
temperature
may
have
significant
consequence
for
native
plant
communities,
ecosystem
services,
and
human
livelihoods.
Because
of
the
strong
interdependence
of
human
and
natural
systems
in
the
Peruvian
Andes,
the
region
is
considered
to
be
particularly
vulnerable
to
the
impacts
of
climate
change
and
environmental
degradation.
Land-­‐cover
change
has
profound
effects
on
ecosystem
structure,
function,
and
associate
ecosystem
services
(Sala
et
al.
2000).
Land
cover
change
is
driven
by
multiple
factors
including
direct
human
impacts
as
well
as
indirect
effects
through
shifts
in
temperature
and
precipitation
regimes
due
to
climate
change.
Throughout
the
Andes,
deforestation,
changes
in
fire
regimes,
conversion
of
land
for
agricultural
uses,
and
increased
grazing
pressure
have
extensively
altered
high
altitude
vegetation
cover).
Vegetation
cover
in
the
Cordillera
Blanca
ranges
from
high
altitude
cloud
forest
on
the
Eastern
slope
to
arid
grassland
(Puna)
mixed
with
shrubs,
remnant
tree
patches,
and
alpine
tundra
on
the
western
slope.
Although
these
grasslands
evolved
with
native
grazing
animals,
increased
grazing
pressure,
particularly
from
cattle,
along
with
traditional
burning
practices
to
renew
pastures,
have
lead
to
significant
degradation
(Cingolani
et
al.
2008).
High
altitude
tree
lines
in
the
Andes
are
formed
almost
exclusively
by
trees
of
the
genus
Polylepis
(Rosaseae).
Polylepis
forests
are
considered
to
be
a
key
ecosystem
in
the
high
Andes
and
are
important
for
biodiversity,
water
quality,
and
soil
retention,
and
are
a
possible
carbon
(C)
sink
(Fjeldsa
2002,
Hoch
and
Korner
2005).
Although
Polylepis
forests
are
thought
to
have
historically
fluctuated
with
climatic
factors
(Gosling
et
al.
2009),
these
forests
have
been
extensively
cleared,
fragmented,
and
degraded
through
human
activities
and
are
currently
considered
to
be
among
the
most
endangered
tropical
mountain
forest
ecosystem
(UNEP-­‐WCMC
2004,
IUCN
2010).
Disturbance
and
degradation
can
also
lead
to
replacement
of
forest
stands
with
more
disturbance
tolerant
shrub
species.
As
global
temperatures
rise,
climatic
conditions
suitable
to
species
will
be
displaced
towards
higher
elevations
and
latitudes
(Loarie
et
al.
2009).
Plant
species
are
predicted
to
experience
range
shifts
and
contractions
as
they
move
their
distributions
to
stay
within
their
thermal
niches
(e.g.,
Chen
et
al.
2011).
Although
such
changes
have
been
documented
in
temperate
areas,
very
few
studies
have
focused
on
the
tropics
despite
increasing
recognition
of
rapid
climate
change
effects,
particularly
in
tropical
mountains
(Feely
et
al.
2013).
Changes
in
vegetation
cover
and
composition
have
direct
consequences
for
biodiversity
and
key
ecosystem
services
and
biogeochemical
processes
such
as
carbon
storage
and
nutrient
cycling.
The
decomposition
of
dead
organic
material
is
a
fundamental
biogeochemical
process
through
its
role
in
the
global
C
cycle
and
in
the
recycling
of
nutrients
to
soil
and
plant
communities.
Changes
in
the
rates
of
decomposition
can
have

major
effects
on
ecosystem
functions.
Understanding
patterns
of
land
cover
change
and
their
consequences
for
ecosystem
process
and
services
is
important
for
long-­‐term
planning
in
critical
regions,
particularly
in
the
context
of
climate
change.
Although
an
increasing
number
of
studies
are
examining
direct
impacts
of
disturbance
on
high
altitude
vegetation
types,
there
is
little
current
information
on
interactions
between
disturbance
and
climate
change,
on
longer-­‐term
shifts
(40+
years)
in
vegetation
cover,
or
effects
on
key
ecosystem
functions.
This
study
combines
remote
sensing
(coarse-­‐scale)
data
with
ground-­‐based
measurements
(fine-­‐scale)
to
examine
patterns
of
land
cover
change
over
the
past
40
years
in
Huascaran
National
Park
(HNP)
and
adjacent
communal
areas
in
the
Cordillera
Blanca,
Peru.
We
aim
to
(1)
assess
changes
in
vegetation
cover
over
time
(1972-­‐2012);
(2)
differentiate
between
anthropogenic
and
climate
factors
affecting
vegetation
cover
in
the
Cordillera
Blanca;
(3)
evaluate
factors
influencing
Polylepis
forest
structure;
and
(4)
test
how
shifts
in
temperature
affect
decomposition
of
organic
material.
METHODS
STUDY
AREA.
The
Cordillera
Blanca
is
the
highest
tropical
mountain
range
in
the
world,
with
over
33
peaks
higher
than
6000
meters
and
hundreds
of
5000+
meter
peaks,
and
it
is
protected
within
the
Huascaran
National
Park.
The
National
Park
was
created
in
1975
and
UNESCO
declared
this
region
important
enough
to
be
designated
the
Huascarán
Biosphere
Reserve
in
1977
and
a
World
Heritage
Site
in
1985.
The
Cordillera
Blanca
is
critical
for
biodiversity
and
as
a
source
of
water
for
the
entire
region
(Silverio
and
Jaquet
2003).
SATELLITE
AND
GROUND
VERIFICATION
METHODS.
Landsat
imagery
from
1972
to
2012
is
classified
at
five
year
intervals
to
delineate
grass,
shrub,
and
forest
boundaries
in
Huascaran
National
Park.
Global
NASA
SRTM-­‐derived
Digital
Elevation
Models
(DEMs)
are
used
to
characterize
elevation/slope/aspect
variations
in
the
ecozone
boundary
shifts.
NOAA’s
Moderate
Resolution
Imaging
Spectroradiometer
(MODIS)
will
be
used
to
analyze
fire
frequency
and
severity.
Normalized
Difference
Vegetation
Index
(NDVI)
and
are
used
to
measure
vegetation
productivity
and
compared
to
climate
variables
such
as
an
ENSO
index.
Net
Primary
Productivity
(NPP)
is
calculated
to
examine
the
overall
impact
of
vegetative
transitions
on
potential
provision
of
ecosystem
services.
Satellite
data
is
verified
using
a
series
of
ground-­‐based
measurements.
Between
2011
and
2013,
volunteers
with
the
America
Climber
Science
Program
measured
an
extensive
series
of
ground
control
points
(>300
10-­‐m-­‐radius
plots)
in
8
major
valleys
and
accessible
slopes
along
the
length
of
the
mountain
range.
Specific
parameters
recorded
at
each
ground
location
include:
UTM
coordinates,
altitude,
aspect,
slope,
geomorphology
(e.g.,
debris
slide,
alluvium,
talus
cone,
colluvial
terrace),
ground
cover
categories
(ecotype,
grass,
moss
needle
leaf
litter),
vegetation
classes,
and
an
assessment
of
human
impacts
–
grazing,
trekking,
campsites,
trash).
In
the
absence
of
measurable
disturbances,
climate
changes
should
be
responsible
for
most
vegetation
variability.
Areas
of
high
human-­‐
induced
impacts
such
as
fire
or
grazing
are
compared
to
more
remote
areas
with
fewer
disturbances
to
evaluate
climate
versus
anthropogenic
drivers
for
change.
VEGETATION
MEASUREMENTS.
In
order
to
assess
if/how
native
forest
stands
have
changed
over
time,
we
are
measuring
the
structure,
composition,
and
patterns
of
regeneration
in
a
series

of
20
Polylepis
forest
stands
throughout
HNP.
Forests
have
been
selected
across
a
gradient
of
disturbance
and
accessibility
in
major
valleys
across
the
Cordillera
Blanca.
We
are
sampling
vegetation
in
10-­‐m-­‐radius
plot
established
at
the
approximate
center
of
each
forest
stand.
All
woody
stems
>
5cm
diameter
are
identified
to
species
level
and
diameter
at
breast
height
(dbh,
ca
1.3
m)
and
height
measured.
All
understory
plant
species
present
in
the
plot
are
noted
and
identified.
Forest
floor
cover
(exposed
soil,
bryophytes,
rock,
coarse
woody
debris)
is
characterized
along
a
10-­‐m
transect.
In
smaller
5×5
m
plots
established
in
both
the
forest
stand
center
and
at
the
forest
edge,
we
identify
and
count
all
woody
sapling
and
seedlings
(>10
cm
height
and
<5
cm
dbh).
LITTER
DECOMPOSITION.
Leaf
litter
from
6
dominant
tree,
shrub,
and
grass
species
were
hand-­‐
collected
in
July
2013.
The
species
were
collected
from
lower
elevation
(3500-­‐3800)
and
higher
elevations
(4500-­‐4800)
ranges
and
represent
a
variety
of
leaf
functional
types.
Litter
decomposition
is
being
evaluated
using
a
litterbag
technique.
Ten
combinations
of
litter
are
placed
in
400
total
litterbags
(fine
mesh
bottom
with
3cm
mesh
on
top
to
allow
arthropod
access)
and
deployed
in
ten
replicate
depots
at
two
elevations
(3800m
and
4400m).
Soil
moisture
and
nutrient
content
is
measured
at
each
depot
and
annual
surface
and
soil
temperature
(5cm
depth)
is
recorded
using
Hobo
data
loggers
at
each
elevation
point.
Litter
mass
loss
and
litter
nutrient
content
will
be
measured
after
one
year.
PRELIMINARY
RESULTS
AND
CONCLUSIONS
The
results
from
the
processed
satellite
images
(selected
years:
1975,
1989,
1996,
2000,
2010)
show
significant
increases
in
NDVI
for
the
protected
area
within
HNP
(Figure
1).
NDVI
increased
in
both
the
3000-­‐4000
m
range
and
in
the
4000-­‐5000m
range.
Changes
in
unprotected
areas
(elevations
below
3000
m)
and
glacier
covered
and
recent
de-­‐glaciated
areas
(above
5000
m)
did
not
show
changes
in
vegetation
productivity
during
this
time
interval.
This
suggests
that
land
management
(i.e.
protection)
within
the
park
has
had
positive
effects
on
vegetation
productivity.
Analysis
of
MODIS
fire
products
shows
that
there
have
been
extensive
burns
within
HNP
between
2002
and
2010
(Figure
2).
Timing
of
fire
events
is
correlated
to
fuel
load
which
is
correlated
with
patterns
of
precipitation
(ENSO
cycles).
Importantly
for
HNP
management,
we
show
that
most
fires
are
anthropogenic
and
originate
within
the
park
and
move
into
the
communal
areas
only
occasionally.
This
is
in
contradiction
to
National
Park
policy
and
is
having
a
direct
effect
on
biogeographic
patterns.

Preliminary
analysis
of
forest
stand
measurements
show
that
seedling
density
is
negatively
correlated
to
grazing
intensity
and
evidence
of
cow-­‐access
to
forest
patches.
Less
disturbed
forest
stands
had
similar
tree
seedling
densities
at
centers
and
edges
whereas
stands
that
showed
signs
of
cow
disturbance
had
lower
overall
seedling
densities
and
few
to
no
seedlings
along
edges.
This
research
will
be
ongoing
in
2013-­‐2014.
ACKNOWLEDGEMENTS
The
American
Climber
Science
Program
(ACSP)
is
a
citizen-­‐science
program
designed
to
facilitate
research
opportunities
for
scientists
in
regions
which
are
difficult
to
access.
Scientists
and
climbers
come
together
for
expeditions
to
collect
data
for
scientific
projects
and
to
share
their
enthusiasm
for
the
mountains.
Research
expeditions
are
also
designed
to
provide
opportunities
for
non-­‐scientists
to
learn
about
scientific
practices
as
well
as
to
instruct
future
scientists
on
safety
in
mountain
regions.
Support
for
this
research
was
provided
by
the
ACSP
volunteer
scientists
and
climbers.
Parque
Nacional
Huascaran
and
the
Universidad
Nacional
Santiago
Antúnez
de
Mayolo
kindly
provided
logistical
support
and
access
to
research
sites.
We
thank
Ricardo
Gómez
López,
Ricardo
Villanueva
Ramírez,
Julio
Palomino
Cadenas,
Martin
Salvador
Poma,
Edson
Ramírez,
and
Chris
Benway.
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